Definition:

EPDM is a type of single ply membrane roof for flat roof applications unlike built up roofing which uses several layers in its installation.

EPDM is a synthetic rubber technically called Ethylene Propylene Diene Monomer. This material is installed as a single thin sheet with a thickness ranging from 0.030 (30 mils) to 0.060 inches (60 mils) thick. The most common thicknesses for residential use are 45 mils and 60 mils.

EPDM material is flexible and to a degree is also resistant to blunt impacts.

Other single ply membrane roofing materials include:

• Neoprene (polychloroprene)
• PVC (polyvinyl chloride)
• Chlorinated polyethylene and chlorosulfonated polyethylene sheets
• Polymer-modified bitumens

EPDM roofs can be installed fully adhered, mechanically fastened or loose laid.

Fully adhered installation is most common for residential applications. The membrane is rolled onto the roof and relaxes. A special bonding adhesive is then applied to th ebottom of the membrane and the roof substrate. The membrane is then pushed into place using a special broom ensuring no bubbles between the two surfaces. The sheets overlap at least 3 inches and are spliced and fastened together with adhesive or a special tape.

Loose laid roofs are held in place with ballast like smooth river rocks and are often called called ballasted roofs. 10 pounds per square foot of ballast is required. Alternatively a precast concrete paver system is sometimes used to hold the roof membrane in place and the roof structure must be designed for this additional weight.

Mechanically fastened roofs attach to the roof deck or insulation directly with specially designed fasteners. This system relies upon sealant to ensure weatherproof integrity.

 

Also called:
Rubber roof